The present invention relates to a catalyst structure and a fuel cell using the same.
Fuel cells have been noticed as energy sources of the next generation, and, recently, fuel cells using, as a fuel, a material other than hydrogen which is difficult to handle are investigated, and methanol is particularly noticed. For example, as disclosed in “Applied Physics”, Vol. 71, No. 8 (2002), pages 1005-1006, fuel cells which produce electricity by direct reaction of methanol at electrodes are called direct methanol fuel cells (DMFC) and researched as fuel cells used for portable devices, etc. The problem of DMFC to be solved is to improve the cell output, and as also disclosed in the above literature (Applied Physics), it is now studied to increase the effective area of catalyst by providing irregularities on the surface of the catalyst, thereby improving catalytic activity.
Furthermore, for example, JP-A-2003-247414 proposes a method for operating an exhaust gas purification apparatus for vehicle internal combustion engines which solves the problem that exhaust gas purification catalyst particles grow at high temperatures to reduce the effective area to cause deterioration of catalytic function. Moreover, as environmental problems become serious, apparatuses for disposal of exhaust gases discharged from factories and power stations are also proposed as disclosed in JP-A-2004-24979.